The Writer's Almanac with Garrison Keillor

On this day in 1752, Benjamin Franklin (books by this author) is believed to have performed his famous kite experiment and proved that lightning is electricity. He tied the kite to a silk string with an iron key on the end of the string. From the key, he ran a wire into a Leyden jar, a container that stored electrical charge. He then tied a silk ribbon to the key, which he held onto from inside a shed, to keep it dry. The electrical charge from the storm overhead passed through the key and into the Leyden jar.

Franklin, as it turns out, was lucky to have conducted this experiment safely. Several others who attempted it after him were electrocuted. He used the information he gained to design lightning rods, which conducted a storm's electrical charge safely into the ground. One of Franklin's lightning rods saved his own house years later, during a storm.

It's the birthday of psychologist and psychoanalyst Erik Erikson (books by this author), born in Frankfurt, Germany (1902). He argued that the human life cycle could be understood as a series of eight developmental stages. He said each stage has its own "crisis" that must be overcome before moving on to the next stage. For adolescents, the crisis is figuring out who you are and what you want to do with your life — and that's where the term "identity crisis" comes from.

It's the birthday of science writer Dava Sobel (books by this author), born in New York City (1947). Her mother was trained as a chemist and her father was a doctor, and she started out as a science writer for IBM. She began freelancing and eventually got a job writing about science for The New York Times. Her big breakthrough came in 1996, when she published Longitude, which tells how the 18th-century scientist and clockmaker William Harrison solved the problem of determining east-west location at sea. Sobel barely had enough money to finish the research for the book, and only 10,000 copies were printed on the first run, but Longitude became a surprise best-seller in America and England.

On this day in 1215, King John of England placed his seal on the Magna Carta, granting basic liberties to his subjects. He wasn't the first English king to grant a charter, but he was the first to have it forced on him by his barons. He had taxed the Church and the barons heavily to fund the Third Crusade, defend his holdings in Normandy, and pay for unsuccessful wars, and England was on the brink of civil war. The charter limited the monarchy's absolute power and paved the way for the formation of Parliament, and it is the nearest thing to a "Bill of Rights" that Britain has ever had. It guaranteed, among other things, that "No free man shall be arrested, or imprisoned, or deprived of his property, or outlawed, or exiled or in any way destroyed, nor shall we go against him or send against him, unless by legal judgement of his peers, or by the law of the land."

Of course, John had no intention of upholding the document, and it was repealed almost immediately on the grounds that he gave his seal under duress. But the idea had taken root, and through a succession of subsequent charters, it became the basis for the British legal system and, in turn, the legal systems of most of the world's democracies. Parts of the United States Constitution were lifted directly from the Magna Carta, and it is so central to our own idea of law that the American Bar Association erected a monument at the meadow of Runnymede. The yew tree, under which the signing is believed to have taken place, still stands.